Carton making machine



July 28, 1959 A. s. GIBB CARTON MAKING MACHINE Filed Dec. 27, 1956 8 Sheets-Sheet 1 INVENTOR A Zex 5. C2 z' &

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A. S. GIBB CARTON MAKING MACHINE July 28, 1959 8 Sheets-Sheet 4 Filed Dec. 27, 1956 INVENT OR e u m a 2 a J l. a W 6 m We 2 9 w, M w W 5- h 5 .5 F 1 e C M. WW m $1 6 u a a w z 69 EU a 1 ii See fa.

Jilly 28, 1959 A. s. GIBB CARTON MAKING MACHINE 8 Sheets-Sheet 6 Filed Dec. 27, 1956 INVEN TOR ATTORNEYS BY WW.

July 28, 1959 A. s. GIBB 2,896,518

CARTON MAKING MACHINE Filed Dec. 27, 1956 8 Sheets-Sheet 8 28 US INVENTOR AZex 5. G [(55 ATTORNEYS United Stew a nt 0.

CARTON MAKING MACHINE Application December 27, 1956, Serial No. 630,938

18 Claims. (Cl. 93- 51) This invention relates to machines for use in the manufacture of cartons from blanks of fiber board, cardboard or the like. More particularly, it relates to such a machine for use in manufacturing tray-like cartons in which to market cans of beer.

Carton forming blanks are fed to the machine and the latter folds flaps of the blanks upwardly, secures them by adhesive and moves each completed carton into a receiver in which it remains an ample time to permit setting of the adhesive. Each blank comprises a rectangular body, side flaps and end flaps joined to said body along fold lines, and corner flaps joined to said side flaps along other fold lines; and the machine provides for such folding of the flaps that none can interfere with the folding of another.

One object of the invention is to provide a novel and advantageous machine which folds thefour corner flaps upwardly to vertical positions near the corners of a rectangular plunger, folds the two side llaps upwardly at the sides of the plunger and thereby swings the corner flaps inwardly to vertical positions at the ends of said plunger, sprays adhesive onto the end flaps, and operates said plunger to depress the partly completed carton'into an underlying rectangular throat frame, thereby causing upward folding of the adhesive-coated end flaps against the vertically positioned corner flaps, provision being made for pressing the corner and end flaps tightly together while in said throat frame, toinsure proper adhesion.

Another object of the invention is to provide a novel, rapid and generally advantageous machine in which the flap folders, the plunger/ and the adhesive spray guns are pneumatically operated, in which the various compressed air lines have coil-actuatedvalves, and in which the complete insertionof any blank "into the machine causes operation of a motor driven timer which completes the circuits of the'valve-actuating coils in such sequence as to cause the required sequential operations.

Yet another object is to provide a rectangular'rec iver extending downwardly from the above mentioned throat frame and dimensioned to snugly retain each completed carton until the latter is eventually depressedby following cartons into a discharge position at the lower end of said receiver, the adhesivebeing thus given ample time to set before carton discharge. i

A further object is to provide novel stationarily mounted cornerflap guides spaced outwardly from the ends of the aforesaid plunger to prevent outward springing of the vertically positioned corner flaps from said plunger ends, the arrangement being such that the upwardly folded corner flaps move between said. guides and said plunger ends as said corner flaps are movedinwardly during upward folding of the carton side flaps.

A still further object is to provide'novel pivoted dogs to engage the upwardly folded carton "side flaps and aid in holding them in vertical positionsagai'nstthe sides, of the plunger as the latter starts its descent into thethroat frame. a

Another object is to provide a novel construction in 2,896,518 Patented July 28, 1959 j 2 which the corner flap guides and the pivoted dogs are all mounted on the lower ends of two fixed cylinders which form parts of the operating means for the plunger.

Yet another object is to provide a novel construction for the plunger in which two plunger end walls are mounted for pneumatic projection to cause the above mentioned pressure of the corner and end flaps together.

Still another object is to provide a novel, durable and trouble-free machine which may be expeditiously manufactured, profitably sold at a reasonable price, and rapidly and efficiently operated.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several viewsillustrated in the accompanying drawings.

In the drawings:

Figure l is a rear elevation, partly broken away and in section, a blank being shown in the machine in readiness for folding.

Figure 2 is a side elevation as indicated. by the arrow 2 of Figure 1, parts being broken away and in section.

Figure 3 is a horizontal sectional view on line 3-3 of Figures 1 and 2, one of the cylinders for plunger end plates being also partly in section.

Figure 4 is a diagrammatic front or rear elevation show ing the corner flaps of the blank upwardly folded (see Figure 42:).

Figures 5 and 6 are respectively a diagrammatic top view and a diagrammatic'side view showing the carton side flaps upwardly folded, the corner flaps moved inwardly at the "endsof the plunger and adhesive applied to the carton end flaps (seeFigure 5a).

Figure 7 is a diagrammatic front or rear elevation partly in section showing the side and end flaps in the same positions as in Figures 5, 6 and 6a, and also showing the end flaps ascending as the plunger starts to descend into the throat frame (see Figure 7a).

Figure 8 is a diagrammatic vertical sectional view showing the carton in completed form and the plunger end plates projected to press the corner flaps tightly against the "end flaps (see Figure 8a).

Figures 4a, 5a, 7a and 8a are perspective views showing the difierent stages of blank folding (see Figures 4, 5 and 6, 7 'and 8 respectively)- Figure 9 is a diagrammatic perspective view showing an illustrative system of compressed air lines and coil-actuated valves for effecting the required pneumatic operations, and also showing an illustrative glue supply means for the glue spray guns;

Figure 10 is an -across-the-line diagram showing the actuating coils for the various coil-actuated valves, an illustrative 'motor-d riven timer for energizing and deenergizing these coils, and the blank-actuated switch for starting the timer motor. a i

Figure 11 is a view similar to Figure 3 but showing the adhesive spray guns differently located.

The mechanical construction and relation of elements will be described in detail by reference to Figures l to 3. Adequate attention'will then be given to the compressed air and glue conducting system, to the various coil-actuated(solenoid) valves, and to the electrical system, without, however, placing over-emphasis on them byfunnecessarily lengthy description.

The construction can best be described after describing theform of blank to be folded by the machine. Oneof these blanks is shown at B in the upper portion o f Figure 3 and in other views; and part of a preceding blank B is also shown inFigure, 3, Each blank B- comprises a rectangular body. B}, side flaps B end flaps B connected along fold lines with said body B and corner flaps B connected along fold lines with the ends of the side flaps B Two spaced tubular standards 20 are secured to and rise rigidly from a base 21, and the upper ends of these standards are rigidly. connected by a horizontally elongated crown 22. Between and spaced from the intermediate portions of the standards 20, a horizontal rectangular throat frame 23 is provided over which to position any blank B to be folded by the machine. This throat frame is internally dimensioned to snugly and frictionally receive each completely folded or set-up carton. Y

A vertically elongated rectangular receiver 24, of openwork construction, extends downwardly from the throat frame 23 and is internally dimensioned to snugly and frictionally receive each carton pushed downwardly from said throat frame by the next carton depressed into said throat frame. Each completed carton will thus remain in the receiver 24 until it is eventually pushed down to the receiver outlet 25 through which it may be re moved by hand or by conveyor.

Two blank-guiding tracks 26 extend horizontally rearward to the inner sides of the standards 20; and two additional tracks 27 extend from the front ends of said tracks 26 to the front side of the throat frame 23 to prevent the blanks B from seriously sagging as they are forwardly fed into position over said throat frame. The insertion of each blank into the machine is limited by a stop bar 28 carried by brackets 29 which project rearwardly from the throat frame 23. This stop bar 28 carries a micro switch S which is closed by a fully inserted blank B and starts the desired sequence of operations. I

In the present disclosure, the rear ends of the guide tracks 26 are secured upon brackets 30 which extend from the ends of the throat frame 23 to the standards 20 and are suitably secured to both said throat frame and said standards. Horizontal plates 31, flush with the upper side of the throat frame 23, extend from the ends of this frame, overlie base flanges 32 of the tracks 26 and are secured to both said frame 23 and said base flanges 32. These plates 31 support the end and corner flaps of the blank B when the latter is in position for folding; and to prevent any blank from catching on said plates 31 while it is being fed to said position, the track base flanges 32 have ribs 33, the upper sides of which are flush with the upper sides of said plates 31.

A rectangular plunger 34 is provided to normally closely overlie only the body B of any blank B; and two vertical cylinder and piston assemblies 35 are provided to support and to operate said plunger 34. The cylinders 36 of these assemblies 35 are secured at 37 at their upper ends to the crown 22; and the piston rods 38 of said assemblies are secured at 39 to the plunger 34. This plunger comprises a bottom 40, front and rear side walls 41 secured to said bottom 40, and projectable end walls or pressure plates 42. The piston rods 38 are secured to the bottom 40. Two flexible counterbalance lines 43 are also secured to the bottom 40, are trained over sheaves 44 mounted in the crown 22, and are attached to plunger counterbalance weights 45 in the tubular standards 20.

Cylinder and piston assemblies 46 are provided in the plunger 34 for projecting the end Walls or pressure plates 42. The piston rods 47 of these assemblies are secured to the walls or plates 42 and each assembly has a rod retracting spring 48 (Figure 3). Compressed air admitted to the cylinders 49 of the assemblies 46 cause projection of the rods 47 and the walls or pressure plates 42; and upon exhaust of air from said cylinders the springs 48 retract these elements 47, 42 to normal positions.

Four corner flap folders 50 are mounted on brackets 51 projecting beyond the ends of the throat frame 23,

said folders being positioned to underlie the corner flaps B of a blank to be folded into carton form. Each folder is in the form of an inclined cylinder and piston assembly, the piston rod of which is upwardly projectable pneumatically and carries a flap engaging head 52. The cylinders 53 of the assemblies 50 are secured to the brackets 51 and each contains a spring 54 (Figure l) for retracting the rod and the head 52 to normal position upon exhaust of air pressure from the cylinder.

Two side flap folders 55 are provided at the front and rear sides of the throat frame 23 in positions to normally underlie the blank side flaps B In the present disclosure, each side flap folder comprises a rock shaft 56 and lateral arms 57 thereon, said rock shaft 56 being mounted in bearings 58 secured to the throat frame 23.

Two substantially vertical cylinder and piston assemblies 59 are provided for raising and again lowering the two side flap folders 55. The cylinders 60 of these assemblies 59 are pivotally mounted at 61 on the front and rear portions, respectively, of the receiver 24, and the piston rods 62 are pivoted at 63 to one arm of the folders 55, respectively.

Four pneumatically actuated glue spray guns 64 are suitably mounted at 65 in positions to apply adhesive for securing the end flaps B and the corner flaps B together. In most views of the drawings, these spray guns are mounted near the corners of the throat frame 23, to overlie the end portions of the end flaps B of the blank being formed into a carton.

Arched brackets 66 are secured to the lower ends of the plunger operating cylinders 36 and rigidly carry two horizontal bars 67 which normally rather closely overlie the plunger end walls or pressure plates 42, respectively, and project beyond the front and rear sides of the plunger 34. The four ends of these bars 67 carry four pivotally hung dogs 68, respectively. The function of these dogs (see Figures 5 and 6) is to aid in holding the blank side flaps B in upright positions against the front and rear walls 41 of the plunger 34 when said side flaps B are upwardly folded by operation of the side flap folders 55.

Prior to upward folding of the side flaps B the corner flaps B are upwardly folded to vertical positions by the corner flap folders 50 (see Figure 4). Consequently, as the side flaps B are upwardly folded, the corner flaps B are swung inwardly at the ends of the plunger 34 (see Figures 5 and 6). The end flaps B to which glue has been applied by the spray guns 64, must then be upwardly folded (see Figures 7 and 8) by depression of the plunger 34 into the throat frame. During this upward folding of the end flaps B it is important that the corner flaps B be restrained against outward springing away from the ends of the plunger 34. Novel provision has been made for so doing.

Two horizontal corner flap guide bars 69 have been provided in outwardly spaced relation with the end walls or pressure plates 42 of the plunger 34, respectively, said guide bars 69 being secured to the outer ends of the above described brackets 66 and being thereby mounted on the cylinders 36. The ends 70 of the guide bars 69 are bent outwardly at obtuse angles to facilitate entrance of the corner flaps B between these bars 69 and the end walls or pressure plates 42 of the plunger 34, and said bars 69 then hold the corner flaps B in the required vertical positions (Figures 5 and 6) in readiness for upward folding of the glue-coated 'end flaps B General operation A blank B is fed into the machine until it strikes the stop bar 28. It (the blank) may be pushed in by the next blank as seen in Figure 3. As this occurs, the blank closes the switch S and the various other operations are performed automatically by the operation of a synchronous motorM which drives a timer T (see Figure 10). The four corn'er flaps B are upwardly folded by the folders 50 (see Figures 4 and 4a): glue is sprayed onto the end flaps B (again see Figures 4 and 4a): the side flaps B are upwardly folded by the folders 55 (see Figures 5 and 6) and these side flaps B move the upwardly folded corner flaps B inwardly between the guide bars 69 and the plunger end walls or pressure plates 42 (again see Figures 5 and 6): the spray guns 64 are stopped: the plunger 34 is lowered by the cylinder and piston assemblies 35 (see Figure 7), resulting in depression of the partly folded blank into the throat frame 23 and consequent upward folding of the glue-carrying end flaps B (see Figures 8 and 8a): the corner flap folders 50 are lowered by the springs 54: the walls or pressure plates 42 are projected by the cylinderand piston assemblies 46 (see Figure 8), thereby pressing the corner flaps B tightly against the end flaps B while the latter are backed up by the ends of the throat frame 23: the pressure plates or walls 42 are retracted by the springs 48: the plunger 34 is raised by the cylinder and piston assemblies 35: the side flap lifters 55 are lowered by the cylinder and piston assemblies 59: and the motor M and timer T stop, completing a cycle and leaving the carton (Figure 8a) in the throat frame 23. The next carton pushes the first carton down in the receiver 24 and so on until said first carton eventually reaches the outlet 25 through which it may be removed by hand or by conveyor.

To facilitate description of the compressed air controlling and conducting means for the various cylinders, the glue system, and the electrical system, the various operations above given are briefly listed below with identifying numbers for later reference.

Operations performed in sequence Compressed air conducting system and glue conducting means (see Fig. 9)

Compressed air is conducted from a tank C to the various cylinders and to the glue guns 64, through a system L of air lines, and glue is conducted through a system L of lines extending from a glue tank G, the top of this tank being supplied with compressed air from the system L to pneumatically feed the glue to the guns.

The system L includes solenoid-actuated valves for controlling the flow of compressed air to the various cylinders and to the glue guns to pneumatically perform operations 3, 4, 5, 7, 9, 11 and 12. These valves, like the rest of the system L have been diagrammatically shown. They have been given the same reference numbers as the operations which they cause, plus the exponent a. For example, the valves 3a cause operation 3 of the above list; the valves 4n cause operation 4, etc.

Pressure regulating valves R and cut ofr valves V may be employed wherever advisable.

Electrical system (see Figure 10) The actuating coils for the solenoid valves 3a, 4a, 5a, 7a, 9a, 11a and 12a have been diagrammatically shown at 3b, 411,512, 712, 9b, 11b and 1212, respectively The timer T, when driven by the synchronous motor M upon closing of the switch S, makes and breaks the circuits of the coils 3b, 4b, 512, etc. in proper sequence bymeans of maintaining and limit switch 10 for the motor M.

The switch for the coils 3b of the valves 3a is denoted at 30; the switch for the coils 4b of the valves 4a is denoted at 4c, etc. each switch being given the same reference number as the operation which it causes plus the exponent c. For example, switch 30 energizes the coil 3b of the valves 3a to perform operation 3 of the above list; switch 4c energizes the coils 4b of the valve 4a to perform operation 4, etc. There is one variation from this general pattern, however, as the switch supplies the coils 11b and 12b of the valves 11 and 12, to simultaneously cause operations 11 and 12.

To recapitulate, switch 30, coils 3b and valve 311 coact to produce operation 3 of the above list: 4c, 4b and 4a cooperate to produce operation 4: 50, 5b and 5a coact to produce operation 5, etc. Operation 1 is caused by the blank B closing the switch S: operation 2 by the closed switch S: operation 6 by conventional construction of the glue spray gun 64 upon re-closing of valves 4a: operation 8 by the spring 54 upon re-closing of valves 3a: and operation 10 by the springs 48 upon re-closing of the valve 911.

The timer T and the various coils may be embodied in any suitable wiring system. For simplicity, an acrossthe-line system W has been diagrammatically shown. This system may well include a step-down transformer W for supplying any of the coils which do not require higher voltage.

While any of the solenoid valves 3a, 4a, 5a, etc. remains closed against compressed air flow, its outlet end is open to the atmosphere, due to the valve construction which per se forms no part of the present invention. Thus, while the valve 7a admits compressed air to the upper ends of the cylinders 36, the lower ends of said cylinders exhaust through the valve 11a and vice versa. Similarly, while valve 5a admits compressed air to the lower ends of the cylinders 60, the upper ends of these cylinders exhaust through the valves 12a and vice versa. Also, while the springs 48 are returning the pistons in the cylinders 49, these cylinders exhaust through the valve 9a. Similarly, while the springs 54 are lowering the pistons within the cylinders 53, these cylinders exhaust through the valves 3a. The travel of compressed air to the various solenoid valves 3a, 4a, etc. is indicated in Figure 9 by light full-line arrows. The travel beyond these valves (upon valve opening) is indicated by the light dotted-line arrows. The travel of the glue to the spray guns 64 is indicated by the heavy-line arrows.

In Figure 11 a variation is shown in which the glue spray guns 65 are mounted in positions to apply the glue to the end flaps B of each blank B before the blank reaches the carton forming station. The operation of these guns may occupy the same place (4) as. in the aforesaid sequence of operations, or may be caused to occupy a different place in the sequence by simply changing the setting of the timer cam 40. When the first blank is properly positioned with its end flaps B under the guns, 'the switch S may be closed by hand to cause glue application and the consequent first operation of the various other elements of the machine will then, of course, be fruitless. After this first operation, however, when the first blank reaches the forming station, this blank will close the switch S and from then on the operation of the machine will be automatic. It is, of course, also feasible to provide a manual switch or a blank controlled switch to cause glue application to the first blank.

From the foregoing, it will be seen that novel and advantageous provision has been disclosed for attaining the desired ends but attention is invited to the possibility of making variations within the scope of the invention. Moreover, glue is to be interpreted as sufiiciently broad to include any suitable adhesive.

I claim: 1. A machine for constructing a carton from a blank having a rectangular body, side and end flaps joined to said body, and corner flaps joined to said side flaps; said machine comprising a rectangular throat frame dimensioned to underlie said body only, a rectangular plunger dimensioned for reception in said throat frame and mounted to normally closely overlie said body, corner flap folders mounted near the corners of said throat frame in positions to underlie said corner fiaps respectively, side flap folders mounted at the sides of said throat frame in positions to normally underlie said side flaps respectively, operating means for raising said corner flap folders to upwardly fold said corner flaps to vertical positions, operating means for raising said side flap folders to upwardly fold said side flaps to vertical positions against the sides of said plunger respectively, thereby moving the vertically positioned corner flaps inwardly at the ends of said plunger, adhesive spray guns mounted in positions to apply adhesive for connecting said corner and end flaps, operating means connected with said plunger for lowering the same to depress the partly folded blank into said throat frame, thereby causing upward folding of the end flaps against the vertically positioned corner flaps, pressing means mounted in position to press said end flaps and corner flaps tightly together while within said throat frame, operating means for said adhesive spray guns, and operating means for said pressing means.

2. A structure as specified in claim 1: all of said operating means being pneumatic and having individual control valves, said control valves having individual actuating coils, a motor-driven timer having individual switches in circuit with said coils respectively for energizing said coils in sequence, a starting switch for the timer motor positioned to be actuated by a blank fed into the machine, and a circuit-maintaining switch for said motor, said circuit-maintaining switch being driven by said timer.

3. A structure as specified in claim 1; together with stationary corner flap guides spaced outwardly from the ends of said plunger for holding the vertically positioned corner flaps against springing away from said ends of said plunger, said corner flaps being movable between said ends of said plunger and said corner flap guides as said side flaps are upwardly folded.

4. A structure as specified in claim 1: said operating means for said plunger including two vertical cylinders fixedly mounted over said plunger, corner flap guides spaced outwardly from the ends of said plunger for holding the vertically positioned corner flaps against springing away from said ends of said plunger, said corner flaps being movable between said ends of said plunger and said corner flap guides as said side flaps are upwardly folded, and means fixedly mounting said corner flap guides on the lower ends of said cylinders.

5. A structure as specified in claim 1; together with pivoted dogs stationarily mounted near the four corners of said plunger in positions to engage said side flaps when the latter are upwardly folded, said dogs being operative to then hold said side flaps against outward springing from said plunger.

6. A structure as specified in claim 1; said operating means for said plunger including two vertical cylinders fixedly mounted over said plunger, pivoted dogs mounted near the four corners of said plunger in positions to engage said side flaps when the latter are upwardly folded, said dogs being operative to then hold said side flaps against outward springing from said plunger, and means fixedly mounting two of said dogs on the lower end of one of said cylinders and the other two of said dogs on the lower end of the other of said cylinders.

7. A structure as specified in claim 1; said plunger having projectable end walls constituting said pressing means, said operating means for said pressing means including cylinder and piston assemblies mounted on said plunger.

8. A machine for constructing a carton from a blank having a rectangular body, side and end flaps joined to said body, and corner flaps joined to said side flaps; said machine comprising a base, two spaced standards rising rigidly from and secured to said base, a crown extending horizontally between and secured to the upper ends of said standards, a horizontal rectangular throat frame between and spaced from the intermediate portions of said standards, said throat frame being dimensioned to underlie the blank body only, horizontal plates extending from the ends of said throat frame toward said standards to support the end flaps of the blank, horizontal blank guiding tracks secured to said standards and positioned to slidably guide the blank onto said plates and said throat frame, a receiver for completed cartons extending downwardly from said throat frame and dimensioned to snugly receive each completed carton, a rectangular plunger over said throat frame in position to closely overlie said body of said blank, said plunger being dimensioned for reception in said throat frame, two cylinder and piston assemblies having vertical cylinders secured to said crown and projecting downwardly therefrom, said assemblies having piston rods secured to said plunger near the ends of the latter, corner flap folders mounted stationarily in positions to underlie and upwardly fold said corner flaps of the blank, side flap folders mounted at the front and rear sides of said throat frame in positions to underlie said side flaps and upwardly fold the same after said corner flaps have been upwardly folded, adhesive spray guns mounted in positions to apply adhesive for connecting said corner and end flaps, and operating means for said cylinder and piston assemblies, said corner flap folders, said side flap folders and said spray guns.

9. A structure as specified in claim 8; together with brackets secured to the lower ends of said cylinders, horizontal corner flap guide bars secured to said brackets and spaced outwardly from the ends of said plunger, horizontal dog-mounting bars also secured to said brackets and overlying the ends of said plunger, said dog-mounting bars projecting beyond the front and rear sides of said plunger, and pivotally hanging dogs on the ends of said dog-mounting bars, said dogs being positioned to engage said side flaps when the latter are upwardly folded, the vertically positioned corner flaps being movable between said guide bars and the ends of said plunger as said side flaps are upwardly folded.

10. A structure as specified in claim 8; said standards being tubular, plunger-counterbalancing weights in said tubular standards, flexible lines connected to said weights and to said plunger, and sheaves over which said lines are trained, said sheaves being mounted on said crown.

11. In a carton constructing machine having a rectangular plunger to overlie the body of a blank having side and end flaps and corner flaps joined to said side flaps; corner flap guides stationarily mounted in outwardly spaced relation with the ends of said plunger; the corner flaps, after being first folded upwardly from said side flaps, being movable between said corner flap guides and the ends of said plunger during upward folding of said side flaps against the sides of said plunger, pivoted dogs mounted near said plunger in position to engage and temporarily hold said side flaps when the latter have been upwardly folded, cylinder and piston assemblies having fixed vertical cylinders above said plunger, said assemblies having piston rods connected to said plunger for operating the latter, and means fixedly mounting said corner flap guides and said pivoted dogs on the lower ends of said cylinders.

12. In a carton constructing machine having a rectangular plunger to overlie the body of a blank having side and end flaps and corner flaps joined to said side flaps; corner flap guides stationarily mounted in outwardly spaced relation with the ends of said plunger; the corner flaps, after being first folded upwardly from said side flaps, being movable between said corner flap guides and the ends of said plunger during upward folding of said side flaps against the sides of said plunger, pivoted dogs mounted near said plunger in position to engage and temporarily hold said side flaps when the latter have been upwardly folded, cylinder and piston assemblies having fixed vertical cylinders above said plunger, said assemblies having piston rods connected to said plunger for operating the latter, said corner flap guides being in the form of horizontal bars, other horizontal bars carrying said pivoted dogs, and brackets to which the first and second named horizontal bars are secured, said brackets being secured to the lower ends of said cylinders.

13. A structure as specified in claim 1; said adhesive spray guns being mounted near the corners of said throat frame to apply the adhesive to a blank under said throat frame.

14. A structure as specified in claim 1; said adhesive spray guns being positioned to apply the adhesive before the blank reaches a position over said throat frame.

15. A structure as specified in claim 8; said adhesive spray guns being mounted near the corners of said throat frame to apply the adhesive to a blank under said throat frame.

16. A structure as specified in claim 8; said adhesive spray guns being positioned to apply the adhesive before the blank reaches a position over said throat frame.

17. In a machine for forming a carton from a blank having a rectangular body, side and end flaps joined to said body, and comer flaps joined to said side flaps; a

rectangular depressible plunger dimensioned to overlie said body only, said plunger having vertical sides and ends, means for guiding the blank into position under said plunger, corner flap guides mounted in outwardly spaced relation with the vertical ends of said plunger, means for folding said corner flaps upwardly from said side flaps and for vertically positioning said corner flaps in readiness for entrance between said. plunger ends and said corner flap guides, means for then upwardly folding said side flaps against the vertical sides of said plunger and thereby causing the vertically positioned corner flaps to enter between said plunger ends and said corner flap guides, means for then lowering said plunger to cause depression of the partially folded blank, and means for upwardly folding said end flaps during said blank depression.

18. A structure as specified in claim 17; together with pivoted dogs mounted near said plunger in position to engage and temporarily hold said side flaps when the latter have been upwardly folded.

References Cited in the file of this patent UNITED STATES PATENTS 2,196,440 Hoza Apr. 9, 1940 2,438,788 Palmer Mar. 30, 1948 2,653,524 Hickin Sept. 29, 1953 2,820,403 Plough et a1. Jan. 21, 1958 2,830,507 Hickin et a1 Apr. 15, 1958 

